An authentication method and an authentication system, which are used for authenticating a product wrapped in a packaging film, were disclosed in EP 2 318 286 B1 and its counterpart US patent publication no. 2011/164748. The packaging film includes pigment particles randomly distributed in one area of the packaging film. A product is then packaged (wrapped, enclosed) using the packaging film that contains the randomly-distributed pigment particles. An identification code is derived (generated) from the relative positional coordinates, and optionally also from the color values, of the pigment particles, in accordance with an encryption algorithm and the identification code is recorded (stored). During the authentication process, a digital image of the area of the packaging film that contains the pigment particles is recorded (generated) by an imaging device. Then, the digital image is evaluated (analyzed) by a computer in order to derive (obtain) a check code from the relative positional coordinates of N different pigment particles, and optionally the color values of the same. The derived check code is then compared to recorded (stored) identification codes to determine whether there is a match. For example, the identification codes may include angular values of one or more polygons having m corners, where m is an integer satisfying the relationship 3≤m≤N and the coordinates of the corners of the polygon correspond to the relative positional coordinates of m pigment particles. Pigment particles may be used, e.g., that luminesce in the range of wavelengths from 100 to 380 nm. In particular, materials that fluoresce in the visible part of the spectrum upon excitation (stimulation) with ultraviolet (UV) light or blue light may be used, such as particles that contain rare earth metals.
DE 10 2004 056 007 A1 discloses a mobile verification device for verification of travel documents. In one embodiment, a mobile communication device such as a mobile phone is used to capture (read, sense) security features on a travel document. For this purpose, the mobile phone may include an illumination unit that may be configured as an attachable module or adapter. Wavelengths in the UV and near-infrared (NIR) regions are used to determine specific security features. Because the travel document is captured (read, sensed) from different viewing angles and at different distances, the images captured by the mobile phone must be normalized into a standard size and equalized.